Synthese der γ-Amino-n-kapronsäure und des α′-Äthyl-α-pyrrolidons

Ohne Zusammenfassung     

Ueber die Alkaloide der Jaborandibl?tter

Ohne Zusammenfassung     

On Preservation Theorems for Two-Variable Logic

We show that the existential preservation theorem fails for two-variable first-order logic FO². It is known that for all k ≥ 3, FO^k does not have an existential preservation theorem, so this settles the last open case, answering a question of Andreka, van Benthem, and Németi. In contrast, we prove that the homomorphism preservation theorem holds for FO².     

Stability of Liquid Layers on Solid Materials

For a class of disjoining pressure potentials the existence of stable liquid layers on solid surfaces is studied. In some cases of solid configurations with simple geometries explicit results are obtained, in particular for a single cylindrical or spherical cavity. No smallness for the thickness of the layer is assumed.